Thermally enhanced NIR up-conversion fluorescence multimode thermometry based on Y2Mo3O12:Nd3+,Yb3+

Abstract

Severe thermal quenching of fluorescence is the main obstacle to the application of fluorescence thermometers in higher temperature regions. In order to broaden the temperature detection range of fluorescence thermometers, the Y₂Mo₃O₁₂:Nd³⁺,Yb³⁺ phosphor with negative thermal expansion (NTE) characteristics was successfully synthesized. The up-conversion (UC) fluorescence thermal enhancement (⁴F_3/2 → ⁴I_9/2) increased 109 times at 480 K and the UC fluorescence lifetime (FL) of the transition ⁴F_5/2 → ⁴I_9/2 increased from 77 to 144.5 μs in the range of 280 to 380 K under the excitation of a 980 nm laser. Herein, a multimode temperature probe was constructed through fluorescence intensity ratio (FIR) technology (⁴F_7/2/⁴F_5/2, ⁴F_7/2/⁴F_3/2 and ⁴F_5/2/⁴F_3/2) and FL technology based on the ladder-like thermally coupled energy levels (TCLs) of Nd³⁺. The feasibility of the probe was verified and Y₂Mo₃O₁₂:Nd³⁺,Yb³⁺ has high stability and accuracy (δT = 0.61 K at 480 K), indicating that it is an ideal candidate in higher temperature monitoring. This work not only proposes an ideal scheme for designing high sensitivity fluorescence thermometers, but also provides a certain reference value for solving the problem of fluorescence thermal quenching.